Captive bolt



E, w. DOWNS ETAL CAPTIVE BOLT Original Filed Feb. 19, 1959 INVENTORS PlziLz'ns FLaCbsse Feb. 23, 1965 3,170,473 CAPTIVE BOLT Ernest W. Downs, Natick, and Philias F. La Casse, Holliston, Mass., assignors to the United States of America,

as represented by the Secretary of the Army Continuation of application Ser. No. 794,478, Feb. 19,

1959. This application Sept. 12, 1962, Ser. No. 228,211

1 Claim. (Cl. 135-3) (Granted under Title 35, US. Code (1.952.), sec. 266) The invention described herein, if patented, maybe manufactured and used by and for the Government for governmental purposes, without the payment to us of bers and purlins, to form the frame structure for a sectional arch and purlin type shelter, in which the frame members are usually in the form of hollow or tubular,

or channel-shaped metal extrusions. It is to be understood, however, that the present invention is equally well adapted for use in attaching any hollow or tubular structural member to any other hollow or solid structural member or support. A specific use for the captive bolt assembly is .as a primary load carrying connection between the purlins and the end arches of tent frames,

especially the male end arch of a light-metal tent frame to provide a rigid frame type of structure, to counteract the forces applied by wind acting longitudinally.

One of the objects of our invention is to provide new and improved means for securing frame members of a sectional arch to the purlinsof a tent structure which are loss-proof and which thereby overcome the problem presented by the excessive loss of conventional bolts heretofore used to connect such structural parts together. A Another object of our invention is to provide a captive bolt, or captive bolt assembly, which is of relatively simple nature, easy to assemble and apply to or remove from the structural frame members or parts, and one which functions as a primary stress carrying unit or member of a frame type structure.

The foregoing and other objects and advantages of the present invention will appear from the following description and appended claim when considered in conjunction with the accompanying drawing forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In said drawing:

FIG. 1 is a fragmentary perspective view of a male end arch and several purlins of a metal tent frame, showing two of the primary stress carrying units, namely, the captive bolts, or assemblies of the present invention, securing the parts together;

FIG. 2 is a top plan view, on an enlarged scale, shoW- ing one of the captive bolt assemblies functioning as a primary stress carrying unit;

FIG. 3 is a View similar to FIG. 2, partly in section, showing the arch, purlin and captive bolt assembly prior to securement of the parts;

FIG. 4 is a further enlarged scale fragmentary vertical sectional view of the assembled parts shown in FIG. 2.

FIG. 5 is a vertical section, partly in elevation, taken substantially along the-line 55 of FIG. 4, looking in the direction of the arrows;

FIG. 6 is a greatly enlarged cross-sectional view of 3,170,473 Patented Feb. 23, 1965 the bolt shank of the captive bolt assembly, showing one form of transverse loss-preventing pin;

FIG. 7 is a view similar to FIG. 6 but showing another form of transverse loss-preventing pin embodying the present invention; and V FIG. 8'is a view similar to FIGS. 6 and 7 showing a transverse threaded stud-like member projecting laterally or transversely from the shank of the captive bolt.

' Before explaining indetail the present invention, it is to be understood that the invention is not limited to its application to the details of construction and arrangement of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of being practiced or carried out in various ways. It is to be understood also that the phraseology or terminology employed herein is for the purpose of description and not of limitation. V V I -A fragment of an end arch, upright supports, and purlins is shown in FIG. 1 of the drawing, the whole unit being indicated at it). The unit, as shown, comprises a sectional arch or arch memberll, supported by whole at 14.

The arch members,supports;and purlins represent a part of a frame structure of a sectional arch and purlintype shelter, such as the purlins and end arch of a tent 7 frame.

The frame members are preferably in the form of hollow, or tubular, or channel-shaped metal extrusions and may be made from aluminum or magnesium, or any of the light-weight metal alloys. This particular type of shelter or tent is adapted to be shipped in knockeddown condition to various bases in military operations, or for other purposes, and must be of such a constructron as to permit the quick and ready assembly of its parts or sections to form the finished structure. It is also essential that the means for attaching or connecting the various parts together be such that they will remain with and as a part of the disassembled part or section without danger of accidental loss or displacement. Into this category falls the captive bolt, or captive bolt assembly 14 of the present invention, being one which, while easy to assemble and to assemble with the parts to be connected together, is provided with the loss-proof means to prevent its being displaced from the part or section to which it is attached.

As seen in FIGS. 2 and 3, the arch member 11 is provided in its forward wall with an opening 15 and in its diametrically opposed rear wall with a similar hole 16 which, however, has slotlikc wing portions 17 (see particularly FIGS?) and 5). The purlin 13 shown in FIGS 2 and 3 has at its forward end a drilled and internally threaded socket 1.3a, the purlin otherwise being preferably of tubular construction.

-Each of the captive bolt assemblies 14 comprises a shank 18 whose inner end portion is externally threaded at 19 and whose opposite end portion is unthreaded but is provided with a transversely drilled opening (not shown). The unthreaded end of shank 18 receives and supports a head 21 which has a drilled opening 22 formed therein which is adapted to register with the drilled opening or passage (not shown) in the bolt shank 18. The head 21 may take any shape or outline, being shown as hexagonal in the drawing. The head 21 is attached to the shank 18 by means of a springy metal split sleeve or tube 23 which is inserted into the hole 22 and into the registering unnumbered hole in shank 18 to hold and releasably lock the head in position against relative movement with relation to the shank l3.

Intermediate its ends, bolt 18 is provided with a sec- 0nd transverse hole or opening 2t) into which is driven a tapered pin 24, see FIG. 6. The pin, as shown, has portions extending or projecting outwardly from opposite sides of shank 18 in substantially a right angle to the axis of'said shank. The captive bolt assembly li -t is carried by and forms a removablepart. of member 111. To assemble the bolt with thearch member 11, the un threaded end of shank 18 is first inserted through hole 1s in the arch member, with the projecting ends of pin 24 passing through the wing-like slots 17- in the wall of the arch member 11. The pin 24, upon axial movement, will contact the walls of the frame member ill and thus prevent' the accidental displacement or dislocation of'the shank 18 from said framemember. Thereafter, to complete the captive bolt asse'mblyli, the head member or portion 21 isapplied to the unthreaded portion of shank 18, the hole 22 bcingaligned with the hole in shank 13, whereupon the springy metal split sleeve is inserted'to hold and releasably lock the head in place-uponthe shank. Arch member 11 is then moved into contact with 'purlin 13 and the bolt tightened down, causing its threads 19 to engage the internal threads 13a of the purlin to releasably lock the parts together. Thus, each of the captive bolts 14 ,serves as a primary stress-carrying unit, or member, and. provides for a rigid structure. it will be understood, of course, that the abovedescribed mode of assembly may vary but would be repeated until the entire framestructure of the tent has been set up.

Whereas, it is a simple matter to assemble the frame members to provide the tent frame,.it is likewise a simple said openings having diametrically arranged, slot-like operation to dismantle them, being merely'necessary'to back, the bolt away from the threaded socket 13a of the purlin 13. The arch member 11 is then removable from the purlin 13 and carries the captive bolt assembly 14 which,-as stated above, is prevented from loss or displacement from the member by virtue of the provisions bolt shank 18 is provided with a threaded recess 27 which extends inwardly from its periphery toward the, center thereof and whichis adapted to receive a threaded stud, or the like 28, having a head 29. In this form, the projecting portionor head 29 of the loss-preventing'mem-- ber will serve to prevent accidental displacement of the captive bolt assembly from the arch or frame 11. Other :1 forms of loss-preventing means may, of course, be sub stituted for the members 2d, 25 or 28.

We claim:

In a knockdown portable tent frame adapated to be assembled and disassembled in thetield, said'tent frame including elongated hollow tubular "structural members having two opposed transverse wall openings, one of wing portions, and elongated stringers adapted to be assembled with said tubular. members at right angles thereto, said stringers having integrally formed therewith screw-threaded end sockets; the combination therewith of loss-proof captive bolt assemblies semi-permanently lodged insaid tubular members, each of said bolt assemblies comprising a shank transversely extending through said wall opening in said-tubular member, one end of said. shank being screw-threaded forlseparable engagement with a screw-threaded end socketin one stringer, said shank having a transverse opening substantially spaced from eitherend'of said shank and so located tha tubular member when said tubular member is not engaged with said stringer, said pin being capable of longi,

tudinal insertion through 'said slot-like wing portions,

a removable large head-on the other end of saidshank for manipulating said shank, and removable locking means for holding said shank and head together. 3

References Cited by the Examiner HARRISON R. MOSELEY, Primary Examiner.

REINALDO P. MACHADO, Examiner. V 

